Here is a good article on the differences between extruder types and some tips. https://pinshape.com/blog/direct-drive-vs-bowden-extruder-guide/

In general, no, Amperage rating alone is not a valid indicator of a given stepper motor’s specifications for a specific duty such as an extruder motor. You have to know the system and any limita...

Here is a pretty good explanation of the limiting factors with 3d printing and speed posted by Jeffrey Meyer: The major limiting factors to the speed are dictated by a fellow named Isaac Newton et al ...

At low layer heights (0.1mm) doing fine detail prints, the individual segments are extremely small extrusion volume. Since volume is a distance of a KNOWN filament diameter being pushed in, extremely ...